1. Field of the Invention
The present invention relates to a wavelength division multiplex transmitter, and particularly to a wavelength division multiplex transmitter for use in optical transmission.
2. Description of the Related Art
In a wavelength division multiplex transmitter used in a wavelength division multiplex communication system (hereinafter called WDM system), it is necessary to set up the number of wavelengths to be used for multiplex.
In a conventional wavelength division multiplex transmitter, the number of wavelengths is determined as the sum of the number of wavelength converters provided in the wavelength division multiplex transmitter, and a user""s inputting number, which is the number of lights directly to be inputted to the wavelength to division multiplex transmitter.
In such a conventional wavelength division multiplex transmitter, however, when a signal light is inputted to the wavelength division multiplex transmitter using no wavelength converter, a manual operation by the user is necessary because it has not a function of automatically setting up the number of wavelengths. It requires much labor to the user, and therefore, is inconvenient.
Besides, in the conventional wavelength division multiplex transmitter, it is impossible to control the setting-up operation of the number of wavelengths by detecting a transmission trouble between its wavelength multiplexer (hereinafter called AWG module) and a signal light source. It is therefore impossible to keep the output power of its optical amplifier at the optimum value for the WDM transmission. This causes a degradation of transmission.
It is an object of the present invention to provide a wavelength division multiplex transmitter capable of automatically setting up the number of wavelengths and detecting a trouble in a transmission path, and so making a WDM transmission with always keeping the whole of the system at the optimum level.
A wavelength division multiplex transmitter according to the present invention for use in a wavelength division multiplex communication system, comprises light detection monitors for detecting light signals inputted to a light signal input part of a wavelength multiplexer, and control means for determining the number of wavelengths to be multiplexed on the basis of the powers of the light signals detected by the light detection monitors.